emissary

Last weekend, I was out for a drive in my 993. I was going about 60 when I suddenly noticed that when I pressed the gas pedal, nothing was happening. I looked down at the instrument panel, and all my indicator lights were on and the tach was at 0rpm...it was basically like I stalled out at 60mph. I pulled over to the side of the road and tried to restart. Initially, the starter would chug vigorously, but the engine wouldn't fire. After waiting a bit, I could intermittently get the engine to fire, but it would die again within half a second or so. The car showed 3/8 of a tank of gas left, and I've run it down below that level before, so I'm fairly confident the car has gas. I ended up having the car towed home.

I have not been able to restart it since (the starter just chugs but the engine doesn't fire). Where it gets interesting is that when I put the key in the ignition and turn it to "on" (without trying to start it), I get a varying, persistent clicking noise from the engine bay. In examining closer, it appears to be a series of two clicks at varying frequency, one coming from the top of the engine, and the other from somewhere in the center of the engine. I also get a fan that starts on/off briefly in the engine bay. I do not believe the fuel pump in the boot is starting; occasionally when the ignition is set to "on" for a bit, I'll hear some sort of light pop from the fuel pump area. It definitely appears I have some sort of electrical issue.

Also interesting, I have a BergvilleFX T-OBD cable that I have used previously to successfully connect to the ECU. When I try to connect now, the clicking will stop, but ScanTool cannot connect (even though it was able to connect successfully a month ago); eventually the clicking noise will resume, but ScanTool never connects.

For what it's worth, I installed a Rennsport Systems GIAC chip about six weeks ago, but I haven't had any issues during those six weeks. Also, I had the airbag code reset on the car a couple of days before this happened.

Does anyone have any ideas I should try before sending it to the shop? Thanks in advance!


UPDATE: 5/24/2016

So I installed the new DME relay, and now I can get the car to start, but it will die shortly there after. It will run for somewhere between 1 second and 60 seconds (the longer times are if I give the engine some consistent mild revs), but eventually it dies with a solid check engine light. Sometimes the engine will sputter a bit while running, and the check engine light will come one while sputtering, and then disappear as the engine resumes normal operation.

I am getting some mild white smoke and a fuel odor when starting the car repeatedly and trying to get it to stay running.

The DME relay definitely plays some sort of role, as when I go back and install the prior relay, I am unable to get the car started; both of the new relays that I purchased produce the behavior above.

Anyone have any more ideas before I send it to the shop? Thanks in advance!

NC TRACKRAT

Try installing a known good DME/Fuel Pump relay.

OverBoosted28

Of course the usual DME/relay check, but what's concerning is the "light pop" sound from FP area up front. Could this "light pop" be an electrical arcing? I'd get car up regardless, pull cover and make sure all connections are clean, secure, and there's been no arcing. Don't wanna BBQ the car.

emissary

Thanks, I just ordered a couple from Amazon to try.

emissary

I probably didn't describe the noise properly. It didn't sound like an electrical short, but rather like a pump that only, well, pumped once...or something like that.

mpruden

That noise sounds like your varioram actuators doing their usual self check. You should be able to visually see them move when you turn the ignition to the on position. If so, it is completely normal.

JM993

almost certainly a fuel delivery problem. if it's not the DME relay, test the fuel pump and fuel pressure.

emissary

I have an early '95 993, so I don't believe I have varioram. The clicking noises also continue indefinitely at a varying rhythm provided the key is left in the ignition and set to "on".

Endoman

Easy to tell VR from non VR. VR inlets are aluminium non VR black plastic.
Very similar syptoms on my car (non VR) a few weeks ago, it was the flywheel speed sensor but DME relay is always first choice and always carry a spare.

mpruden

You're correct. No varioram on a 95.

AOW162435

I vote for malfeasance on the part of the aging DME relay.




Andreas

KNS

I'm assuming this is the same thing as the crankshaft position senor (AKA reference sensor)? Part No 996 606 105 00.

emissary

Thanks all. I ordered a couple of DME relays that should arrive tomorrow; I'll try swapping mine out and will report back.

Porsche_993

I had almost the same issue with my 1995 a few weeks ago. Replaced the DME and it still wouldn't start. Had to tow it to the shop and they have still not figure out the issue.

kevin2012

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